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95 \end{array} |
95 \end{array} |
96 \] |
96 \] |
97 |
97 |
98 \item What is the purpose of the record regular expression in |
98 \item What is the purpose of the record regular expression in |
99 the Sulzmann \& Lu algorithm? |
99 the Sulzmann \& Lu algorithm? |
100 |
100 |
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101 \item Recall the functions \textit{nullable} and \textit{zeroable}. |
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102 Define recursive functions \textit{atmostempty} (for regular expressions |
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103 that match no string or only the empty string), \textit{somechars} (for regular |
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104 expressions that match some non-empty string), \textit{infinitestrings} (for regular |
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105 expressions that can match infinitely many strings). |
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106 |
101 |
107 |
102 %\item (Optional) The tokenizer in \texttt{regexp3.scala} takes as |
108 %\item (Optional) The tokenizer in \texttt{regexp3.scala} takes as |
103 %argument a string and a list of rules. The result is a list of tokens. Improve this tokenizer so |
109 %argument a string and a list of rules. The result is a list of tokens. Improve this tokenizer so |
104 %that it filters out all comments and whitespace from the result. |
110 %that it filters out all comments and whitespace from the result. |
105 |
111 |